What is the function of digestive enzymes?
Enzymes are the organic compounds produced by the living cells to carry forward the biochemical reactions in and outside the cells of the organisms. Some chemical reactions occurs by the enzymes known as catalysis and the substances by which these chemical reactions occurs known as catalytic compounds. Enzymes are of two types- intracellular enzymes or Extracellular enzymes. Intracellular enzymes remain inside the cell also known as endoenzymes. Extracellular enzymes leaves the cells and functions outside the cell also known as exoenzymes.
Extracellular enzymes contain digestive enzymes which help in the breaking down of the food. Digestive enzymes like- salivary amylase or ptyalin secreted by salivary gland in the oral cavity, pepsin (activated from pepsinogen by HCL), rennin (activated from prorenin by HCL), gastric lipase all three produced by the gastric glands in the stomach, pancreatic lipase, pancreatic amylase, DNase, RNase, trypsin (activated from trypsinogen by enterokinase), chymotrypsin (activated from chymotrypsinogen by trypsin) secreted from pancreas in the small intestine, lysozyme in tears, intestinal amylase, maltase, isomaltase, lactase, dipeptidase, intestinal lipase, nucleotidase, nucleosidase, enterokinase they are produced from the intestinal gland in the small intestine.
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
How is the amount of urine produced regulated?
What criteria do we use to decide whether something is alive?
What are the different ways in which glucose is oxidised to provide energy in various organisms?
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm. (c) chloroplast.
(b) mitochondria. (d) nucleus.
What are the differences between autotrophic nutrition and heterotrophic nutrition?
What are outside raw materials used for by an organism?
What would be the consequences of a deficiency of haemoglobin in our bodies?
What are the components of the transport system in highly organised plants?
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
In evolutionary terms, we have more in common with
(a) a Chinese school-boy.
(b) a chimpanzee.
(c) a spider.
(d) a bacterium.
Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
Name a mirror that can give an erect and enlarged image of an object.
Find out, from Table 10.3, the medium having highest optical density. Also find the medium with lowest optical density.
Material medium |
Refractive index |
Material medium |
Refractive index |
Air | 1.0003 | Canada Balsam |
1.53 |
Ice | 1.31 | ||
Water | 1.33 | Rock salt | 1.54 |
Alcohol | 1.36 | ||
Kerosene | 1.44 | Carbon disulphide |
1.63 |
Fused quartz |
1.46 | ||
Turpentine oil |
1.47 | Ruby | 1.71 |
Benzene | 1.50 | Sapphire | 1.77 |
Crown glass |
1.52 | Diamond | 2.42 |
Table 10.3 Absolute refractive index of some material media
Can any source of energy be pollution-free? Why or why not?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
How do auxins promote the growth of a tendril around a support?
Give an example of a double displacement reaction other than the one given in activity 1.10.
A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic make-up of the tall parent can be depicted as
(a) TTWW
(b) TTww
(c) TtWW
(d) TtWw
Why is the use of iodised salt advisable?